Rotary drilling rig for pore-forming of large-diameter drilled pile and construction method

Abstract

The invention belongs to the technical field of rotary drilling rigs, and discloses a rotary drilling rig for large-diameter drilled pile hole forming and a construction method.The rotary drilling rig comprises a drilling rig body, a mounting frame arranged on the drilling rig body, a drill rod arranged on the mounting frame and a drill bit arranged at the lower end of the drill rod; the lower end of the drill rod is fixed to the top of the protective cover, a cleaning mechanism used for cleaning the inner wall of the drill bit is arranged on the drill bit and comprises a cleaning assembly and a driving assembly, and the cleaning assembly comprises a rotating block rotationally installed on the inner top wall of the drill bit and an L-shaped cleaning unit fixed to the side wall of the rotating block. The side, away from the rotating block, of the L-shaped cleaning unit abuts against the inner wall of the drill bit, and the driving assembly is used for driving the rotating block to rotate. The inner wall of the drill bit can be cleaned conveniently, and the situation that the normal use of the rotary drilling rig is affected due to the fact that much soil adheres to the inner wall of the drill bit is avoided.

Description

Technical Field

[0001] The invention relates to the technical field of rotary drilling rigs, and in particular to a rotary drilling rig for drilling large-diameter bored piles and a construction method. Background Art

[0002] The rotary drilling rig is a construction machine suitable for drilling holes in building foundation projects. It is mainly suitable for construction of sand, clay, silty soil and other soil layers. It is widely used in various foundation constructions such as cast-in-place piles, continuous walls, and foundation reinforcement. The so-called rotary drilling rig for drilling holes for large-diameter bored piles is a drilling rig with a larger diameter drill bit, and the drilled holes can be placed in large-diameter bored piles.

[0003] A Chinese patent application document with publication number CN108301782A discloses a rotary drilling rig, including a traveling device, a control panel, a mast, a drill rod and a drill bucket. A power head is elastically connected below the drill rod, a drill bucket is connected below the power head, and a bucket door is connected below the drill bucket. As the drill bucket continues to drill as the drill rod rotates and presses downward, soil is loaded into the bucket through an opening at the bottom of the drill bucket. When the drill bucket is full, the drill bucket moves out of the pile hole, the bucket door is driven to open, and the soil falls out of the drill bucket under its own weight.

[0004] With respect to the above-mentioned related technologies, the inventors believe that the following defects exist: when drilling in highly viscous soil, the highly viscous soil has a certain adsorption to the inner wall of the drill bucket and is not easy to fall off from the drill bucket, which has a certain impact on the further drilling process of the rotary drilling rig. Therefore, it is necessary to improve the design of the related technologies. Summary of the invention

[0005] In order to solve the above problems, the present invention provides a rotary drilling rig for drilling large-diameter bored piles and a construction method.

[0006] The above technical objectives of the present invention are achieved through the following technical solutions: a rotary drilling rig for drilling large-diameter bored piles, comprising a drilling rig body, a mounting frame arranged on the drilling rig body, a drill rod arranged on the mounting frame, and a drill bit arranged at the lower end of the drill rod, a protective cover being fixed to the upper end of the drill bit, the lower end of the drill rod being fixed to the top of the protective cover, a cleaning mechanism for cleaning the inner wall of the drill bit being arranged on the drill bit, the cleaning mechanism comprising a cleaning assembly and a driving assembly, the cleaning assembly comprising a rotating block rotatably mounted on the inner top wall of the drill bit and an L-shaped cleaning unit fixed to the side wall of the rotating block, the side of the L-shaped cleaning unit away from the rotating block being pressed against the inner wall of the drill bit, and the driving assembly being used to drive the rotating block to rotate.

[0007] By adopting the above technical solution, when there is a lot of soil sticking to the inner wall of the drill bit, in order to ensure the normal use of the rotary drilling rig, the staff only needs to drive the rotating block to rotate through the driving assembly, so that the L-shaped cleaning unit rotates synchronously and cleans the inner wall of the drill bit. The cleaned soil falls under the action of gravity, so that the rotary drilling rig can continue the drilling operation.

[0008] Furthermore, the driving assembly includes an electric push rod fixed to the top of the drill bit and located in a protective cover, a movable plate fixed to the upper end of the output rod of the electric push rod, and a center rod fixed to the lower end of the movable plate. The center rod passes through the top of the drill bit and cooperates with the drill bit gap. A circular hole is penetrated on the rotating block for the center rod to pass through. The driving assembly also includes a push column fixed to the inner wall of the circular hole, and a spiral groove is provided on the outer wall of the center rod to slide with the push column.

[0009] By adopting the above technical solution, when the driving assembly is used to drive the rotating block to rotate, the staff only needs to start the electric push rod and move the movable plate downward, and the center rod moves downward synchronously with the movable plate. Since the spiral groove on the center rod slides with the push column in the rotating block, the rotating block and the L-shaped cleaning unit rotate synchronously to complete the action of cleaning the inner wall of the drill bit.

[0010] Furthermore, a scraper is fixed to the lower end of the center rod, and the edge of the scraper is provided with a scraper groove that is snap-fitted with the vertical section of the L-shaped cleaning unit, and the side wall of the scraper is in contact with the inner wall of the drill bit.

[0011] By adopting the above technical solution, when the center rod moves downward, the scraper moves synchronously with the center rod, and the scraper groove on the scraper scrapes off the soil adhered to the vertical section of the L-shaped cleaning unit.

[0012] Furthermore, the L-shaped cleaning unit includes a horizontal part and a vertical part, the horizontal part includes a shell fixed on the outer wall of the rotating block, a sliding plate slidably matched with the inner wall of the shell, a connecting rod fixed to the side of the sliding plate away from the rotating block, and a spring fixed between the side wall of the sliding plate away from the rotating block and the inner wall of the shell, the connecting rod passes through the side wall of the shell and slidably matches, the side wall of the vertical part is fixed to the end of the connecting rod away from the rotating block at a position close to the upper end of the vertical part, the inner wall of the drill bit is provided with a receiving groove that is snap-fitted with the vertical part, the side of the vertical part away from the rotating block is pressed against the inner wall of the drill bit, and the protective cover and the drill bit are jointly provided with a pulling component for pulling the vertical part and making the vertical part disengage from the receiving groove.

[0013] By adopting the above technical solution, when drilling with the drill bit, the vertical part enters the receiving groove under the elastic force of the spring, reducing the probability that the horizontal part of the vertical part of the L-shaped cleaning unit will break due to the resistance of the soil. When cleaning the inner wall of the drill bit, the staff only needs to pull the vertical part through the pulling assembly to make the vertical part disengage from the receiving groove, so that the vertical part is pressed against the inner wall of the drill bit under the elastic force of the spring, and the electric push rod is used to drive the vertical part to rotate, thereby cleaning the inner wall of the drill bit.

[0014] Furthermore, the pulling assembly includes a fixing plate fixed on the inner top wall of the protective cover, a motor fixed on the fixing plate, a winding wheel fixed to the output end of the motor, a traction rope wound on and fixed on the winding wheel, and a sphere fixed to the free end of the traction rope. The center rod is penetrated by a center hole coaxially arranged with the center rod for the traction rope to pass through, the scraper is provided with a reserved hole for the traction rope to pass through, the traction rope passes through the vertical part and cooperates with it, and a spherical groove for accommodating the sphere is provided on the side of the vertical part away from the rotating block.

[0015] By adopting the above technical solution, when using the pulling assembly to drive the vertical part out of the receiving groove, the staff only needs to start the motor. After the motor works, it drives the winding wheel to rotate, so that the traction rope cooperates with the ball and pulls the vertical part, so that the connecting rod and the sliding plate cooperate and compress the spring until the vertical part is out of the receiving groove, and the vertical part is driven to rotate by the electric push rod to clean the inner wall of the drill bit.

[0016] Furthermore, a mounting groove is provided on the top of the scraper, the length of the mounting groove is smaller than the diameter of the center rod, two fixed pulleys are rotatably installed in the mounting groove, and the traction rope passes through the gap between the two fixed pulleys and cooperates with both fixed pulleys to realize the transformation of the traction rope from a vertical state to a horizontal state.

[0017] By adopting the above technical solution, the two fixed pulleys cooperate with each other, so that the traction rope completes the transition from a vertical state to a horizontal state, reducing the wear of the traction rope.

[0018] Furthermore, the scraper is composed of two semicircular plates, a vertical plate is fixed to the bottom of each semicircular plate, and the two vertical plates are fixedly connected by bolts and nuts.

[0019] By adopting the above technical solution, it is convenient for workers to install the fixed pulley and part of the traction rope in the scraper.

[0020] The present application also discloses a construction method of a rotary drilling rig for drilling large-diameter bored piles, comprising the following steps: S1. The drilling rig body controls the lowering of the drill rod and the rotation of the drill bit to realize the drilling of the reserved hole for bored piles; S2. To clean the dirt adhering to the inner wall of the drill bit, the staff only needs to start the motor and drive the winding wheel to rotate. The winding wheel pulls the vertical part through the traction rope and the ball, so that the vertical part is separated from the receiving groove; S3. Start the electric push rod, which drives the movable plate and the center rod to descend. Since the spiral groove on the center rod slides with the push column in the rotating block, and the rotating block is rotatably installed on the inner top wall of the drill bit, the rotating block rotates, and the vertical part is pressed against the inner wall of the drill bit under the action of the spring, so that the vertical part of the L-shaped cleaning unit cleans the inner wall of the drill bit, ensuring the subsequent normal use of the rotary drilling rig.

[0021] In summary, the present invention has the following beneficial effects: 1. In this application, when there is a lot of soil sticking to the inner wall of the drill bit, in order to ensure the normal use of the rotary drilling rig, the staff only needs to drive the rotating block to rotate through the driving assembly, so that the L-shaped cleaning unit rotates synchronously and cleans the inner wall of the drill bit. The cleaned soil falls under the action of gravity, so that the rotary drilling rig can continue the drilling operation; 2. In the present application, when the driving assembly is used to drive the rotating block to rotate, the staff only needs to start the electric push rod and move the movable plate downward, and the center rod moves downward synchronously with the movable plate. Since the spiral groove on the center rod slides with the push column in the rotating block, the rotating block and the L-shaped cleaning unit rotate synchronously to complete the action of cleaning the inner wall of the drill bit; 3. In the present application, during the downward movement of the center rod, the scraper moves synchronously with the center rod, and the scraper groove on the scraper scrapes off the soil adhering to the vertical section of the L-shaped cleaning unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is a schematic diagram of the overall structure of an embodiment of the present invention; Figure 2 yes Figure 1 A schematic diagram for highlighting the internal structure of the drill bit; Figure 3 It is a structural schematic diagram of an embodiment of the present invention for highlighting a cleaning mechanism; Figure 4 is a structural schematic diagram of an embodiment of the present invention for highlighting an L-shaped cleaning unit; Figure 5 yes Figure 4 A magnified schematic diagram of center A.

[0023] In the figure: 1, drilling rig body; 2, mounting frame; 3, drill rod; 4, drill bit; 41, receiving groove; 5, protective cover; 6, cleaning mechanism; 61, cleaning assembly; 611, rotating block; 6111, round hole; 612, L-shaped cleaning unit; 62, driving assembly; 621, electric push rod; 622, movable plate; 623, center rod; 6231, spiral groove; 6232, center hole; 624, pushing column ; 7. Scraper; 71. Scraper trough; 72. Reserved hole; 73. Mounting groove; 74. Fixed pulley; 8. Horizontal part; 81. Shell; 82. Sliding plate; 83. Connecting rod; 84. Spring; 9. Vertical part; 91. Spherical groove; 10. Pulling assembly; 101. Fixed plate; 102. Motor; 103. Winding wheel; 104. Traction rope; 105. Sphere; 11. Semicircular plate; 111. Vertical plate. DETAILED DESCRIPTION

[0024] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application; obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments, and all other embodiments obtained by ordinary technicians in this field based on the embodiments in the present application without making creative work are within the scope of protection of the present application.

[0025] like Figure 1-5 As shown, the embodiment of the present application discloses a rotary drilling rig for drilling large-diameter bored piles, comprising a drilling rig body 1, a mounting frame 2 arranged on the drilling rig body 1, a drill rod 3 arranged on the mounting frame 2, and a drill bit 4 arranged at the lower end of the drill rod 3, a protective cover 5 is fixed to the upper end of the drill bit 4, the lower end of the drill rod 3 is fixed to the top of the protective cover 5, and a cleaning mechanism 6 for cleaning the inner wall of the drill bit 4 is arranged on the drill bit 4. The cleaning mechanism 6 includes a cleaning assembly 61 and a driving assembly 62. The cleaning assembly 61 includes a rotating block 611 rotatably mounted on the inner top wall of the drill bit 4 and an L-shaped cleaning unit 612 fixed to the side wall of the rotating block 611, the side of the L-shaped cleaning unit 612 away from the rotating block 611 is pressed against the inner wall of the drill bit 4, and the driving assembly 62 is used to drive the rotating block 611 to rotate.

[0026] When there is a lot of soil sticking to the inner wall of the drill bit 4, in order to ensure the normal use of the rotary drilling rig, the staff only needs to drive the rotating block 611 to rotate through the driving assembly 62, so that the L-shaped cleaning unit 612 rotates synchronously and cleans the inner wall of the drill bit 4. The cleaned soil falls under the action of gravity, so that the rotary drilling rig can continue the drilling operation.

[0027] The driving assembly 62 includes an electric push rod 621 fixed to the top of the drill bit 4 and located in the protective cover 5, a movable plate 622 fixed to the upper end of the output rod of the electric push rod 621, and a center rod 623 fixed to the lower end of the movable plate 622. The center rod 623 passes through the top of the drill bit 4 and is gap-matched with the drill bit 4. A circular hole 6111 is penetrated on the rotating block 611 for the center rod 623 to pass through. The driving assembly 62 also includes a pushing column 624 fixed to the inner wall of the circular hole 6111. A spiral groove 6231 is provided on the outer wall of the center rod 623 to slide with the pushing column 624.

[0028] When using the driving assembly 62 to drive the rotating block 611 to rotate, the staff only needs to start the electric push rod 621 and move the movable plate 622 downward, and the center rod 623 moves downward synchronously with the movable plate 622. Since the spiral groove 6231 on the center rod 623 slides with the push column 624 in the rotating block 611, the rotating block 611 and the L-shaped cleaning unit 612 rotate synchronously to complete the action of cleaning the inner wall of the drill bit 4.

[0029] A scraper 7 is fixed to the lower end of the center rod 623, and a scraper groove 71 is provided on the edge of the scraper 7 to engage with the vertical section of the L-shaped cleaning unit 612, and the side wall of the scraper 7 is in contact with the inner wall of the drill bit 4. When the center rod 623 moves downward, the scraper 7 moves synchronously with the center rod 623, and the scraper groove 71 on the scraper 7 scrapes away the soil adhering to the vertical section of the L-shaped cleaning unit 612.

[0030] The L-shaped cleaning unit 612 includes a horizontal portion 8 and a vertical portion 9. The horizontal portion 8 includes a shell 81 fixed on the outer wall of the rotating block 611, a sliding plate 82 slidably matched with the inner wall of the shell 81, a connecting rod 83 fixed to the side of the sliding plate 82 away from the rotating block 611, and a spring 84 fixed between the side wall of the sliding plate 82 away from the rotating block 611 and the inner wall of the shell 81. The connecting rod 83 penetrates the side wall of the shell 81 and slidably matches. The position of the side wall of the vertical portion 9 near the upper end of the vertical portion 9 is fixed to the end of the connecting rod 83 away from the rotating block 611. The inner wall of the drill bit 4 is provided with a receiving groove 41 that is snap-fitted with the vertical portion 9. The side of the vertical portion 9 away from the rotating block 611 is pressed against the inner wall of the drill bit 4. The protective cover 5 and the drill bit 4 are jointly provided with a pulling component 10 for pulling the vertical portion 9 and making the vertical portion 9 disengage from the receiving groove 41.

[0031] When drilling with the drill bit 4, the vertical portion 9 enters the receiving groove 41 under the elastic force of the spring 84, reducing the probability that the horizontal portion 8 of the vertical portion 9 of the L-shaped cleaning unit 612 is broken due to the resistance of the soil. When cleaning the inner wall of the drill bit 4, the staff only needs to pull the vertical portion 9 through the pulling assembly 10 to make the vertical portion 9 disengage from the receiving groove 41, so that the vertical portion 9 is pressed against the inner wall of the drill bit 4 under the elastic force of the spring 84, so that the vertical portion 9 is driven to rotate by the electric push rod 621, and then the inner wall of the drill bit 4 is cleaned.

[0032] The pulling assembly 10 includes a fixing plate 101 fixed on the inner top wall of the protective cover 5, a motor 102 fixed on the fixing plate 101, a winding wheel 103 fixed to the output end of the motor 102, a traction rope 104 wound on and fixed on the winding wheel 103, and a sphere 105 fixed to the free end of the traction rope 104. A center hole 6232 coaxially arranged with the center rod 623 and for the traction rope 104 to pass through is provided on the center rod 623, a reserved hole 72 for the traction rope 104 to pass through is provided in the scraper 7, the traction rope 104 passes through the vertical part 9 and cooperates with it, and a spherical groove 91 for accommodating the sphere 105 is provided on the side of the vertical part 9 away from the rotating block 611.

[0033] When using the pulling assembly 10 to drive the vertical part 9 out of the receiving groove 41, the staff only needs to start the motor 102. After the motor 102 works, it drives the winding wheel 103 to rotate, so that the traction rope 104 cooperates with the ball 105 and pulls the vertical part 9, so that the connecting rod 83 and the sliding plate 82 cooperate and compress the spring 84 until the vertical part 9 is out of the receiving groove 41, and the vertical part 9 is driven to rotate by the electric push rod 621 to clean the inner wall of the drill bit 4.

[0034] A mounting groove 73 is provided on the top of the scraper 7, and the length of the mounting groove 73 is smaller than the diameter of the center rod 623. Two fixed pulleys 74 are rotatably installed in the mounting groove 73. The traction rope 104 passes through the gap between the two fixed pulleys 74 and cooperates with the two fixed pulleys 74 to realize the transition of the traction rope 104 from a vertical state to a horizontal state, thereby reducing the wear of the traction rope 104.

[0035] In order to facilitate the staff to install the fixed pulley 74 and part of the traction rope 104 in the scraper 7, the scraper 7 is composed of two semicircular plates 11, and a vertical plate 111 is fixed to the bottom of each semicircular plate 11. The two vertical plates 111 are fixedly connected by bolts and nuts.

[0036] The use principle of a rotary drilling rig and construction method for drilling large-diameter bored piles in this embodiment is as follows: when there is a lot of soil sticking to the inner wall of the drill bit 4, in order to ensure the normal use of the rotary drilling rig, the staff only needs to drive the rotating block 611 to rotate through the driving assembly 62, so that the L-shaped cleaning unit 612 rotates synchronously and cleans the inner wall of the drill bit 4. The cleaned soil falls under the action of gravity, so that the rotary drilling rig can continue the drilling operation.

[0037] This embodiment also discloses a construction method of a rotary drilling rig for drilling large-diameter bored piles, comprising the following steps: S1, the drilling rig body 1 controls the drill rod 3 to descend and the drill bit 4 to rotate, thereby achieving the drilling process of the bored pile reserved hole 72; S2. To clean the dirt adhering to the inner wall of the drill bit 4, the worker only needs to start the motor 102 and drive the winding wheel 103 to rotate. The winding wheel 103 pulls the vertical portion 9 through the traction rope 104 and the ball 105, so that the vertical portion 9 is separated from the receiving groove 41; S3. Start the electric push rod 621, which drives the movable plate 622 and the center rod 623 to descend. Since the spiral groove 6231 on the center rod 623 slides with the push column 624 in the rotating block 611, and the rotating block 611 is rotatably installed on the inner top wall of the drill bit 4, the rotating block 611 rotates, and the vertical portion 9 is pressed against the inner wall of the drill bit 4 under the action of the spring 84, so that the vertical portion 9 of the L-shaped cleaning unit 612 cleans the inner wall of the drill bit 4, ensuring the subsequent normal use of the rotary drilling rig.

[0038] The above is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, some improvements and modifications without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. A rotary drilling rig for drilling large-diameter bored piles, comprising a drilling rig body (1), a mounting frame (2) arranged on the drilling rig body (1), a drill rod (3) arranged on the mounting frame (2), and a drill bit (4) arranged at the lower end of the drill rod (3), wherein: A protective cover (5) is fixed to the upper end of the drill bit (4), and the lower end of the drill rod (3) is fixed to the top of the protective cover (5). The drill bit (4) is provided with a cleaning mechanism (6) for cleaning the inner wall of the drill bit (4). The cleaning mechanism (6) comprises a cleaning assembly (61) and a driving assembly (62). The cleaning assembly (61) comprises a rotating block (611) rotatably mounted on the inner top wall of the drill bit (4) and an L-shaped cleaning unit (612) fixed to the side wall of the rotating block (611). The side of the L-shaped cleaning unit (612) away from the rotating block (611) is pressed against the inner wall of the drill bit (4), and the driving assembly (62) is used to drive the rotating block (611) to rotate.

2. A rotary drilling rig for drilling large diameter bored piles according to claim 1, characterized in that: The driving assembly (62) comprises an electric push rod (621) fixed to the top of the drill bit (4) and located in the protective cover (5), a movable plate (622) fixed to the upper end of the output rod of the electric push rod (621), and a center rod (623) fixed to the lower end of the movable plate (622), wherein the center rod (623) passes through the top of the drill bit (4) and is clearance-matched with the drill bit (4), and a circular hole (6111) is provided on the rotating block (611) for the center rod (623) to pass through, and the driving assembly (62) further comprises a pushing column (624) fixed to the inner wall of the circular hole (6111), and a spiral groove (6231) is provided on the outer wall of the center rod (623) for slidingly matching with the pushing column (624).

3. A rotary drilling rig for drilling large diameter bored piles according to claim 2, characterized in that: A scraper (7) is fixed to the lower end of the center rod (623), and the edge of the scraper (7) is provided with a scraper groove (71) that is snap-fitted with the vertical section of the L-shaped cleaning unit (612), and the side wall of the scraper (7) is in contact with the inner wall of the drill bit (4).

4. A rotary drilling rig for drilling large diameter bored piles according to claim 3, characterized in that: The L-shaped cleaning unit (612) comprises a horizontal portion (8) and a vertical portion (9), wherein the horizontal portion (8) comprises a shell (81) fixed on the outer wall of the rotating block (611), a sliding plate (82) slidably matched with the inner wall of the shell (81), a connecting rod (83) fixed to a side of the sliding plate (82) away from the rotating block (611), and a spring (84) fixed between a side wall of the sliding plate (82) away from the rotating block (611) and the inner wall of the shell (81), wherein the connecting rod (83) passes through the side of the shell (81) and is The vertical portion (9) is fixed to the side wall of the vertical portion (9) near the upper end thereof and is fixed to the end of the connecting rod (83) away from the rotating block (611); the inner wall of the drill bit (4) is provided with a receiving groove (41) which is snap-fitted with the vertical portion (9); the side of the vertical portion (9) away from the rotating block (611) is pressed against the inner wall of the drill bit (4); and the protective cover (5) and the drill bit (4) are jointly provided with a pulling component (10) for pulling the vertical portion (9) and allowing the vertical portion (9) to be separated from the receiving groove (41).

5. A rotary drilling rig for drilling large diameter bored piles according to claim 4, characterized in that: The pulling assembly (10) comprises a fixing plate (101) fixed on the inner top wall of the protective cover (5), a motor (102) fixed on the fixing plate (101), a winding wheel (103) fixed on the output end of the motor (102), a traction rope (104) wound on and fixed to the winding wheel (103), and a sphere (105) fixed to the free end of the traction rope (104); a center hole (6232) coaxially arranged with the center rod (623) and for the traction rope (104) to pass through is provided on the center rod (623); a reserved hole (72) for the traction rope (104) to pass through is provided in the scraper (7); the traction rope (104) passes through the vertical part (9) and cooperates with it; a spherical groove (91) for accommodating the sphere (105) is provided on the side of the vertical part (9) away from the rotating block (611).

6. A rotary drilling rig for drilling large diameter bored piles according to claim 5, characterized in that: The scraper (7) is provided with a mounting groove (73) at the top, the length of the mounting groove (73) being smaller than the diameter of the center rod (623), two fixed pulleys (74) being rotatably mounted in the mounting groove (73), the traction rope (104) passing through the gap between the two fixed pulleys (74) and cooperating with the two fixed pulleys (74) to realize the transformation of the traction rope (104) from a vertical state to a horizontal state.

7. A rotary drilling rig for drilling large diameter bored piles according to claim 5, characterized in that: The scraper (7) is composed of two semicircular plates (11), a vertical plate (111) is fixed at the bottom of each semicircular plate (11), and the two vertical plates (111) are fixedly connected by bolts and nuts.

8. A construction method of a rotary drilling rig for drilling large diameter bored piles according to any one of claims 1 to 7, characterized in that: The steps include: S1, the drilling machine body (1) controls the drill rod (3) to descend and the drill bit (4) to rotate, thereby achieving the drilling process of the bored pile reserved hole (72); S2. To clean the dirt adhering to the inner wall of the drill bit (4), the worker only needs to start the motor (102) and drive the winding wheel (103) to rotate, and the winding wheel (103) pulls the vertical part (9) through the traction rope (104) and the ball (105), so that the vertical part (9) is separated from the receiving groove (41); S3, start the electric push rod (621), the electric push rod (621) drives the movable plate (622) and the center rod (623) to descend, because the spiral groove (6231) on the center rod (623) and the push column (624) in the rotating block (611) are slidably matched, and the rotating block (611) is rotatably installed on the inner top wall of the drill bit (4), so that the rotating block (611) rotates, and the vertical part (9) is pressed against the inner wall of the drill bit (4) under the action of the spring (84), so that the vertical part (9) of the L-shaped cleaning unit (612) cleans the inner wall of the drill bit (4), thereby ensuring the subsequent normal use of the rotary drilling rig.

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